1. Field of the Invention
This invention relates to a shield-processing structure of a shielded cable which is formed by ultrasonically welding the shielded cable and an earth cable together, using two resin members.
2. Related Art
One conventional shield-processing structure, using ultrasonic welding, is disclosed in Unexamined Japanese Patent Publication 2001-6767. This shield-processing structure is formed, using two resin members 50 and 51 shown respectively in FIGS. 7A and 7B. The resin members 50 and 51 have shielded cable-receiving grooves 50b and 51b of an arcuate shape formed respectively in their joint surfaces 50a and 51a, and a resin-flowing recess 50c is formed in the joint surface 50a while resin-flowing recesses 51c are formed in the joint surface 51a. The resin member 50 has earth cable-holding projections 50d (each having a flat distal end surface) each formed between the shielded cable-receiving groove 50b and the resin-flowing recess 50c, while the resin member 51 has earth cable-holding projections 51d (each having a flat distal end surface) each formed between the shielded cable-receiving groove 51b and the corresponding resin-flowing recess 51c. 
Next, a shield-processing procedure will be described. An earth cable 53 is placed on a shielded cable 52 (having a conductor 52a covered at its outer periphery with a braided wire (shielding covering member) 52) in intersecting relation thereto, and that portion where the earth cable 53 is placed on the shielded cable 52 is held between the two resin members 50 and 51, and ultrasonic vibration is applied from an ultrasonic horn to the two resin members 50 and 51 while exerting a compressive force between the upper and lower resin members 50 and 51.
When the ultrasonic vibration is thus applied by the ultrasonic horn, the resin members 50 and 51, an outer insulating sheath 52d of the shielded cable 52 and an outer insulating sheath 53b of the earth cable 53 are melted by the vibration energy produced by application of the ultrasonic vibration, so that a conductor portion 53a of the earth cable 53 and the braided wire 52c of the shielded cable 52 are contacted with each other. When the melted portions are solidified after the application of ultrasonic vibration is finished, the two resin members 50 and 51 are integrally connected together, so that the shielded cable 52 and the earth cable 53 are joined together.
When the shielded cable 52 and the earth cable 53 are held between the two resin members 50 and 51 for the purpose of effecting the ultrasonic welding, the shielded cable 52 is received in the shielded cable-receiving grooves 50b and 51b of the resin members 50 and 51, while the earth cable 53 is pressed between each mating pair of earth cable-holding projections 50d and 51d of the resin members 50 and 51, and in this condition ultrasonic vibration is applied. Therefore, when the outer insulating sheath 53b of the earth cable 53 is melted by heat produced upon application of ultrasonic vibration, the conductor 53a, so far restrained by the outer insulation sheath 53b, is released, and can freely move over the flat earth cable-holding projections 50d and 51d. Therefore, the conductor 53a is disengaged from the earth cable-holding projections 50d and 5d, and are liable to become loose as shown in FIGS. 11 and 12. When the conductor 53a thus became loose, a cable-holding force to hold the shielded cable 52 and the earth cable 53 together was lowered. And besides, good contact between the conductor 53a and the braided wire 52c was not obtained, so that the electrical connection performance was lowered.